// Copyright 2020 Google LLC

struct VSOutput
{
[[vk::location(0)]] float3 Normal : NORMAL0;
[[vk::location(1)]] float3 Color : COLOR0;
[[vk::location(2)]] float Visible : TEXCOORD3;
[[vk::location(3)]] float3 ViewVec : TEXCOORD1;
[[vk::location(4)]] float3 LightVec : TEXCOORD2;
};

float4 main(VSOutput input) : SV_TARGET
{
	if (input.Visible > 0.0)
	{
		float3 N = normalize(input.Normal);
		float3 L = normalize(input.LightVec);
		float3 V = normalize(input.ViewVec);
		float3 R = reflect(-L, N);
		float3 diffuse = max(dot(N, L), 0.0) * input.Color;
		float3 specular = pow(max(dot(R, V), 0.0), 8.0) * float3(0.75, 0.75, 0.75);
		return float4(diffuse + specular, 1.0);
	}
	else
	{
		return float4(float3(0.1, 0.1, 0.1), 1.0);
	}
}